Problem: $\dfrac{1}{3} + \dfrac{2}{6} = {?}$
Answer: ${\dfrac{1}{3}}$ ${\dfrac{2}{6}}$ $+$ ${\dfrac{1 \times 2}{3 \times 2}}$ ${\dfrac{2 \times 1}{6 \times 1}}$ $+$ ${\dfrac{2}{6}}$ ${\dfrac{2}{6}}$ $+$ $ = \dfrac{{2} + {2}}{6} $ $ = \dfrac{4}{6}$